It is important to trim your grape vine back annually because simply this is how it grow stronger and produce better fruits the coming season. Without trimming, the grape vine will produce thin weak shoots that will suck all the vine's energy and produce small tasteless grapes. If you are looking for training grape vines from new plant to a full canopy, then this will be discussed on another post.
When to prune grape vines?
Timing of grape vine pruning is very important for one essential reason; you want to avoid the bleeding of the stored nutrients. If you trim in the wrong time, like when the vine is actively growing, you might end with a dead or shrunk vine. It is important to prune the grape vine when it is dormant after the leaves has fallen which is usually in the coldest weeks of the winter. You can look at the average monthly temperature for your area and determine the lowest temperature week and trim then. Roughly talking, most grape vines are fully dormant towards the middle of January in the areas that has more than one season.
How to prune grape vines?
It is important to use clean pruning shears to cut the shoots and branches to avoid infection and damage to the growing buds. You can clean your tools with 70% isopropyl alcohol. The rule of thumb is to cut the grape vine branches as follows:
- Keep one node on those that have the thickness of the pinky finger
- keep up two nodes on those that have the thickness of the index finger
- keep up to three nodes on those that have thickness of the thumb finger
Keeping more nodes than discussed above will create unnecessary volume overload that will consume the stored nutrients and make the crop looks tiny with no taste. The less nodes you leave, the healthier the shoot growth and bulkier grape bunches will grow. Cut off the small twitches as they grow during the season from the main trunk and between the main canes as those suckers can also decrease the overall thickness of the next season shoots growing distally on the vine.